The invention relates generally to multiple-layer web processing and, more particularly, to a method and apparatus for changing the type of corrugated paper product web produced by a corrugator machine.
It is well-known to produce various types of corrugated paper products from a single corrugator machine. Such a machine can include one or more component machines, known as single facers, which form single ply webs such as kraft paper into a fluted medium, or spacer, and fuse the medium to a second single ply web known as a liner. The laminated liner-medium may be joined to another liner, or to a liner-medium composite, in a machine known as a double backer. The double backer can thus produce single or double-ply corrugated fiberboard in a continuous composite web.
The output of the double-backer can be supplied to various types of processing machines such as rotary shears, slitter/scorers, and material handling equipment, collectively known as the "dry end" of the corrugator machine. The dry end also generally includes one or more knives for cutting the continuous composite web into individual boards or blanks. The individual component machines of the corrugator can be controlled as a unit as is well-known in the art.
Such corrugator machines can produce a wide variety of composite web material by providing various gauges and widths of individual web material to the single facers, and adjusting the dry end of the machine to produce various widths, lengths and configurations of individual fiberboard blanks. However, when the processing for one order of blanks of a given configuration has been completed, a significant amount of time is required using prior art practices to alter the adjustable configuration of the corrugator machine and produce blanks for a second order having a different set of specifications. The steps involved in such an order change may include replacing the supplies of individual web material feeding the single facers and double backer, adjusting the web guides throughout the machine to accommodate a different size of raw material, and changing the operating program of the dry end of the corrugator to slit the continuous web into different widths or cut it into different length blanks.
A corrugator machine is an expensive, fast, high-output machine. Thus, it is desirable not only to minimize the production downtime during an order change, but also to eliminate waste material to the greatest extent possible. It is therefore an objective of the present invention to operate the various components of the corrugator machine so that material for a new order is fed in proper sequence to produce a composite web which changes from the composition of the old order to the composition of the new order with a minimum of waste and lost production time.
A specific problem in achieving an order change in a corrugator machine which provides a multiple-ply output web material is to synchronize the splices of the various web components so that these splices are coincident when the individual web components are formed together into the composite web output. One method of achieving synchronous splices is to slow down the corrugator machine and activate a single splicer for an individual web component. The operator visually tracks the splice and activates the second splicer at what is estimated to be the proper time to achieve coincidence of the two splices. In a similar manner, the remaining splices are produced by the operator running from one splicer to the next, and actuating each one in sequence. In this manner, splices are provided in each of the individual components which may be reasonably coincident at the output of a double backer. However, trial and error methods associated with such an approach are time consuming and often inaccurate, resulting in individual web component splices which could be separated by as much as 100 feet from other component splices. Accordingly, a significant amount of waste material is produced.
Attempts have been made to provide synchronous splicing with reduced down time and increased accuracy by sensing either indicia preprinted onto the individual web component material or magnetic indicators such as tape applied to the individual web component material. Although some success was achieved by these methods in the prior art, printed indicia required special processing of the input web component materials during manufacture, and magnetic sensing methods required an operator to physically place the magnetic tape indicators at the proper position. This task complicated the duties of the operator of the corrugator machine and, in any case, resulted in only a limited improvement in the amount of down time required during an order change.
It is therefore an additional objective of the present invention to provide an apparatus and method for an order change in a corrugator machine which will require neither specially processed input materials nor an excessive amount of operator intervention.